Geochemistry Of Harmful Components In Soils Of Urban And Suburban Areas Of Baotou, Inner Mongolia

The objective of this study is to develop a systematic method for soil quality classification and geochemical warning. We systematically investigated geochemistry of soils and dusts in urban and suburban areas of Baotou City, Inner Mongolia and characterized geochemical distributions of elements, pollution by harmful components and soil quality.Areal enrichment of elements is found in surface soil of the study region of Baotou. Heavy metals (Hg, Cd, Pb, Cu, Zn), rare-earth and radioactive elements (La,U,Th) and other elements (F, P, S) show enrichment. Polluted soils by toxic components were identified in the areas of plants and tailings dams of Baotou Iron & Steel (Group) Co., Ltd., the area from east Donghequ District to Baotou Aluminum Co., Ltd., mid-lower reaches of Kundulun River and village of Sidaoshahe. Contents of elements in dusts are higher than in soils. Rare-earth elements and Fluorine are extraordinarily enriched in dusts compared to soils, which may be caused by discharges from steel and aluminum related plants.Nemorow Pollution Indices assessment indicated that the areas of plants and tailings dams of Baotou Iron & Steel (Group) Co., Ltd. have been seriously contaminated, where soil quality is under category V. In other areas of Baotou City, the soil quality is between category I and II.Croplands in suburban Baotou are pollution-free and soils are basically in categories Ⅰ and Ⅱ. Heavy metals (Cd, Zn, Pb, Cu) in vegetables are less than the limits set by national standards for pollution-free foods and green foods. Fluorine seems suspicious in terms of the contents in vegetables. Whereas, it is difficult to assess its impacts on food chain because there is no national standards available. Our investigation results on local people didn’t indicate symptoms of Fluorine poisoning.Abnormal Radioactivity was measured in tailings dams and slagheaps of Baotou Iron & Steel (Group) Co., Ltd. From 1993 to date,interviews with nearby residents showed notably higher incidences of cancer, osteoporosis and other diseases compared with the rest areas of Baotou.Study of organic pollutants shows that polycyclic aromatic hydrocarbons predominantly originated from combustion of coal and petroleum by largr scale industrial enterprises and secondarily from discharges of industrial waste water, dump, and industrial leaking as well as atmospheric deposition. Assessment studies of Polycyclic aromatic hydrocarbons(PAHS) manifested that soils in Baotou are safe according to Canadian standards for croplands.We developed a computer-based system to perform environmental warning of soil pollution. The software acquires soil survey data, produces maps of soil quality categories and highlights polluted sites and vulnerable areas. The research helps the administrations to monitor, warn and handle pollution accidents.